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Guide to Linux Installation and Administration, 2e2 Objectives In this chapter, you will: •Understand how the X Window System functions •Review the installation and settings of the X Window System •Use popular graphical desktop interfaces

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Guide to Linux Installation and Administration, 2e3 Understanding the X Window System •The installation program automatically detects your graphical hardware and configures the graphical environment •The foundation of that environment is the software that communicates with the video card and makes all other graphical interaction possible Valued Gateway Client:

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Guide to Linux Installation and Administration, 2e4 A Brief History of X •The X Window System was developed by MIT and DEC •The X Window System was released as public domain software in 1985 •The XFree86 Project created a version of X for Intel-based Linux and Unix

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Guide to Linux Installation and Administration, 2e5 Technical Concepts behind X •Developers of X designed a text-based configuration file that lets the user write the driver for any video card •The Xfree86 Project and Linux vendors developed configuration utilities to set up or refine the graphical configuration

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Guide to Linux Installation and Administration, 2e7 Components of the X Window System

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Guide to Linux Installation and Administration, 2e8 Exploring X Components •Each user can select a window manager, desktop interface, and configuration options for that desktop •A window manager or desktop interface provides the user interface to X •Older, basic window managers like fvwm and twm are still in use

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Guide to Linux Installation and Administration, 2e13 Exploring X Components •Graphical libraries make it easier to create new graphical applications by sharing programming code and system resources •Two graphical libraries are associated with the Gnome and KDE Desktops: –Qt (on which KDE is based) –GTK+ (on which Gnome is based)

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Guide to Linux Installation and Administration, 2e14 Displaying X Clients Remotely •The DISPLAY variable or display command-line option controls remote display of X applications •A remote host must permit an application to be displayed by another computer using xhost or xauth functionality •With the xauth system you can restrict access to those users on a remote system who have a specific token (cookie) in order to use the X server

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Guide to Linux Installation and Administration, 2e16 Running the X Window System •X Window System is configured during installation •To configure X after installation, you can use utilities, such as Xconfigurator, xf86config, and others

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Guide to Linux Installation and Administration, 2e17 Configuring X •To use XFree86 packages, a window manager, and a desktop interface, configure the X server software to use a video card and a monitor correctly •You can make changes in the configuration of a window manager or desktop environment

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Guide to Linux Installation and Administration, 2e18 The Configuration File •When X Windows System is launched, it relies on the XF86Config-4 configuration file plus a number of scripts that define which X applications should be launched •The configuration file for XFree86 is located in the /etc directory, in the /etc/X11 directory, or in the /usr/X11R6/lib/X11

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Guide to Linux Installation and Administration, 2e19 Using Xconfigurator •The Xconfigurator program creates an XF86Config-4 file for your XFree86 X server using a menu-driven text-based interface •Xconfigurator probes your hardware and lets you select choices from lists of options

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Guide to Linux Installation and Administration, 2e24 Launching X •The standard method to launch X is to execute the startx command •The startx command automatically executes a number of other commands that launch the X server and run the programs that make up the graphical environment •Each X client is started as a background application •A background application is an application that does not prevent the program that started it from going on to other tasks

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Guide to Linux Installation and Administration, 2e25 The Start-up Process for the X Window System

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Guide to Linux Installation and Administration, 2e28 Using Desktop Interfaces •A desktop interface is a graphical environment that provides a collection of functions and utilities •Some types of information may be much easier to work with in a graphical format •Linux desktop interfaces are KDE and Gnome

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Guide to Linux Installation and Administration, 2e32 The KDE Control Center

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Guide to Linux Installation and Administration, 2e33 The Gnome Desktop •Gnome is a desktop interface very similar to KDE •Gnome uses a GPL license •Gnome provides a set of productivity applications and system administration utilities similar to those included with KDE

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Guide to Linux Installation and Administration, 2e36 Using a Graphical Login Screen •The graphical login prompt is provided by the xdm program •The xdm versions specific to KDE and Gnome are called kdm and gdm, respectively •xdm restarts automatically to provide a graphical login screen •xdm selects which programs to start based on the session chosen by the user

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Guide to Linux Installation and Administration, 2e38 Summary •The X Window System is a graphical environment developed by MIT and DEC in 1985 •Components of X include – X server: interacts with the video card –X client: graphical application what uses the services of the X server •A window manager or desktop interface provides the user interface to X •Qt and GTK+ are the most widely used graphical libraries

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Guide to Linux Installation and Administration, 2e39 Summary •The DISPLAY variable or display command-line option controls remote display of X applications •Xconfigurator and xf86config utilities are used to configure X after installation •Graphical applications include X resources what can be configured •KDE and Gnome are popular desktop interfaces •The graphical login prompt is provided by the xdm program, or the kdm or gdm versions for KDE or Gnome